The time it takes for 1g of strontium-90 to decay to 250 mg is; 57.6 years
<h3>What is the half life of an element?</h3>
The formula for half life is;
A(t) = A₀ * (¹/₂)^(t/t_1/2)
Where;
A(t) is amount left after t years
A₀ the initial quantity of the substance that will undergo decay;
t_1/2 is the half-life of the decaying quantity.
We are given;
t_1/2 = 28.8 years
A₀ = 1 g
A(t) = 250 mg = 0.25 g
Thus;
0.25 = 1 * (¹/₂)^(t/28.8)
log 0.25 = (t/28.8) log (1/2)
-0.60206 = (t/28.8) * -0.3010
t = 2 * 28.8
t = 57.6 years
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Answer: There is a weak, positive correlation between the weight Lucy lost and the number of weeks.
Explanation:
The correlation coefficient is used to measure the relationship between two variables in terms of how they move in relation to one another.
If two variables are said to have a positive correlation, it means that they increase at the same time and decrease at the same time for example, there is a positive correlation between the amount of food a family buys and how much money they have because the more money they have, the more food they buy.
Negative correlations are the reverse for instance Ice cream sales and cold temperatures. The colder it is, the less people buy ice cream.
The Correlation coefficient ranges from -1 to +1 with +1 (-1) meaning that the variables are perfectly positively(negatively) correlated. The closer the value is to 0, the weaker the correlation.
Generally, for a correlation coefficient between the numbers 0 and +0.3, there is a weak positive correlation.
With a correlation coefficient of 0.0502, there is therefore a weak, positive correlation between the weight Lucy lost and the number of weeks.
It can cause forced labor in many parts of the world
Answer: C. II, IV, I, III
Explanation:
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